[MITgcm-support] topography with OBCS

[Andreas Klocker]

Hi,

I am trying to set up a regional model configuration with OBCS. For some reason the model seems to introduce salinities where I actually have bathymetry (see attached figure; bathymetry left, salinities right). Salinities this low definitely do not exist in the files containing the bounday conditions. Is it necessary to set the open boundary exactly to where I have ocean, or should the bathymetry file take care of this by telling the model there should be nothing happening in case of zero water depth?

Here's my data.obcs file:

# Open-boundaries
 &OBCS_PARM01

 OB_Iwest  = 600*1,
 OB_Ieast  = 600*-1,
 OB_Jsouth = 2600*1,
 OB_Jnorth = 2600*-1,

 useOBCSsponge    = .TRUE.,
 useOBCSbalance   = .TRUE.,
 useOBCSprescribe = .TRUE.,

 useOrlanskiWest  = .FALSE.,
 useOrlanskiEast  = .FALSE.,
 useOrlanskiSouth = .FALSE.,
 useOrlanskiNorth = .FALSE.,

 OBWuFile = 'OWU',
 OBWvFile = 'OWV',
 OBWtFile = 'OWT',
 OBWsFile = 'OWS',

 OBEuFile = 'OEU',
 OBEvFile = 'OEV',
 OBEtFile = 'OET',
 OBEsFile = 'OES',

 OBSuFile = 'OSU',
 OBSvFile = 'OSV',
 OBStFile = 'OST',
 OBSsFile = 'OSS',

 OBNuFile = 'ONU',
 OBNvFile = 'ONV',
 OBNtFile = 'ONT',
 OBNsFile = 'ONS',

# OBCS_monitorFreq= 86400.,
# OBCS_monSelect = 1,
 &

# Orlanski parameters
 &OBCS_PARM02
# Cmax=0.45,
# cVelTimeScale=1000.,
 &

 &OBCS_PARM03
 Urelaxobcsinner=864000.,
 Urelaxobcsbound=86400.,
 Vrelaxobcsinner=864000.,
 Vrelaxobcsbound=86400.,
 spongeThickness=40.,
 &

Thanks in advance!
Andreas


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